Which command adds the group class with a GID of 312?

Which command adds the group class with a GID of 312?

A.
newgrp g 312 class

B.
groupadd g 312 class

C.
groupadd n class:312

D.
addgroup g 312 n class

Explanation:

The syntax is: /usr/sbin/groupadd g GID -name